Method and apparatus for handling finely divided materials



G. NIEM Jan' l 1952 Ammon Ann APPARATulsT-on HANDLING 2580581 FINELY nIvrnEn MATERIALS Find April 1, 194e INVENTOR @ar/mko ,we/w72A BY @QM ATTORNEYS Patented Jan. l, 1952 METHOD APPARATUS FR HANDLING FINELY lDIVIDED MATERIALS Gerhard Niemitx, New York, N. Y.,

Kennedy-Van Saun- Manufacturing neering Corporation, New York, N. Y.,

ration of Delaware o assigner to t Engia corpo Application April l, 1946, Serial No. 658,849 3 Claims. ((1302-28) My invention relates to improvements in method and apparatus for handling finely-di-l vided materials such as pulverized coal, ilnely ground ores. cements and other materials which are conveniently handled in a stream of gas or air and which are commonly distributed to various points of use. y

Finely-pulverized materials are commonly handled in air streams and the material delivered to bins or other containers, In the usual practice, however, the air in which -the pulverized material is carried is discharged into the atmosphere along with certain amounts of extremely fine particles which consequently illl the atmosphere with dust and create more or less' of a nuisance 'or inconvenience. Such practices also waste considerable quantities of material which is in itself of considerable importance.

According to my invention I have discovered that iinely-divided materials may be economically distributed to various points of use in a system in which the very finely-divided material normally retained in the air stream and discharged into the atmosphere is kept in a closed cycle and thereby brought back to the initial point at which the pulverized material is mingled with the air stream.

The primary object therefore of my invention is to provide an improved method for economically handling pulverized materials without incurring the waste and nuisance ordinarily encountered.

Another obiect of my invention is to provide In improved apparatus or system in which pulverized materials may be handled in a novel manner without loss and without contaminating the atmosphere in the neighborhood of the plant.

According to the features of my invention, the improved method includes the steps of suspending the pulverized material to be distributed, in an air stream of considerable velocity, passing the resulting mixture through a main duct connecting a series of utilization or distribution points, and at each such point withdrawing a portion of the stream, separating pulverized material therefrom and passing the air of such stream portion back into the main duct'at such point or directly beyond such point. 'I'he process also preferably includes the step of passing the main air stream after it has passed beyond or through the last utilization unit or point in the series back to the intake of the main duct system to supply at least in part the air stream for initially suspending the pulverized or finely-divided material to be distributed by the process.

, 2 I'he system or apparatus preferably employed iii-connection with my improved method includes a large storage bin for pulverized material, a.4

centrifugal fan adapted to provide a stream of air, `means for distributing pulverized material from the bin into the stream oi' air created by the fan, a series of distribution units including a separator for pulverized material, a main duct from said fan extending along said distribution units, means for withdrawing a portion of the stream from said duct into the separator of each unit, means for conducting separated air from Yeach separator back into the main duct at the position of each unit preferably beyond. the point of withdrawal of the portion of the stream, and means for recycling the air in the main duct froma point beyond the series of distribution units back to the intake of the fan.

My invention includes other features, objects and advantages which will be described in detail hereinafter in connection with the accompanying drawing forming a part of this application.

The single figure o1' the drawing is an elevational diagrammatic view showingcertain apparatus elements associated together in a special manner suitable for carrying out my improved method.

Referring to the drawing, the pulverized material which is to be handled in accordance with my invention is introduced into the apparatus as a suspension in an air stream through a duct `Ill which discharges into the upper portion of a cyclone separator i2. For purposes ot illustra tion, I will consider the material being handled to bepulverized coal and that it is desirable to supply pulverized coal to a plurality or series of points of use in a plant such. for example, as an iron foundry or steel mill in which pulverized coal is used as fuel at a number of points in the plant, such as in various types of furnaces and heat-treating units.

In the drawing, the pulverized coal introduced into the separator I2 is for the most part separated from the air stream and conducted into a large storage bin Il from which it is supplied at a predetermined rate as required through a feed valve i8 in a supply tube i8. The tube il discharges into an air stream in a duct 2U provided with a control valve 22. 'I'he air stream in the duct 20 'is induced by means of a centrifugal fan 24 which delivers the mixture oi' pulverized coal and air through a main duct 2l of relatively large diameter which carries the mixture of pulverized coal and air to the various points of use around the plant. two of such points of utilization or distribution units AEach of these utilization units or distributing utilized.

atadas-1 3 f I arcshowninthedrawing.

means as shown includes a cyclone separator 2l which discharges pulverized material through a duct 30 either into a storage bin I2 or through a valve controlled branch duct 34 directly to the furnace in which the pulverized coal is to be The bin 32 provides a small reserve storage of pulverized coal which may be fed at a regulated rate through a feed valve 3l.

Each of the distribution units is supplied with a portion of the stream of pulverized coal and airin the main duct 26 through a valved branch line I8 which discharges directly into the upper portion of the separator 2l. At the position of each distributionunit the main duct 28 is provided with a valve 40 which may be turned to aid in forcing a portion ofthe stream in the duct 2l linto the branch lines Il. The quantity of material taken through each of 'thelines It is controlled by the valve therein in conjunction with the adjacent valve 40 in the duct 28. The air discharged from the centrifugal separators 28 is conducted back into the main duct 26 through lines 42 respectively beyond the valves I0 for the particular units.

From the foregoing description of the apparatus, it will be apparent that all of the air delivered by the fan 24 is kept in the duct system and returned to the main duct 26. At the end of the series of distri-bution units the whole stream may be passed through the final unit separator if desired. In any case the air stream, which may contain some ilnely-divided material and which in fact may contain the excess of pulverized coal not required by the entire series of distribution units is passed into a' return duct 4l which preferably discharges into the upper` portion of a cyclone separator i6, which is adapted to separate most of the remaining pulverized material in the air stream and re-deliver it through a tube 48 into the large storage bin I 4. The air from theV cyclone separator 48 together with the air from the separator I2 is passed through an air duct SII into the intake duct 20 for the blower 24. The system is therefore entirely closed so that if desired the air in the system may be continuously recycled so that no dust will be discharged into the atmosphere and there will be no appreciable loss of pulverized coal or of other materials handled by the process. If necessary for the size oi' the installation one or more booster gzers may be provided in ducts 2G or 4l or in The pulverized coal or other material to be handled by the process and apparatus may be supplied to the bin Il by other means than in a stream of air passed through the duct I0. However, if the duct I0 is utilized along with the III will exceed the quantity required for the blower 24. Under other conditions in view of the natural and incidental air loss in the system, a certain amount of make-up air will be necessary gas after separation 4 operation of the valve 22. This valve may beclosed as desired so that blower 244 applies suction if desired on one or both of the separators I2 and 'Ifhe process and apparatus of the present invention isparticularly suited to the handling of pulverized coal in an air stream in the manner described above but it may be utilized for the handling of other pulverized materials particularly where it is desired to distribute such materials to various points of use, storage or process'- ing. The pulverized material, for example, stored in the series or plurality of bins 32 may be supplied to separate processing units or to separate manufacturing units in which the pulverized material is changed or utilized in the manufacture of various products. Furthermore, other gases than air may be used as a carrier, such as Na, CO2, inert or reactive gases. Where the term air is used it is understood to cover any gas.

From the foregoing description, it will be apparent that certain modiilcations may beV made in the apparatus as well as in the process and still achieve substantially all oi' the benefits and advantages referred to above. Such changes are contemplated as coming within the scope of the appended claims. i

What I claim as new is:

l. An apparatus for handling finely-divided materials comprising a main duct, means for creating a gas stream in the duct, a main supply bin, means for supplying finely-divided material from the main supply bin to the gas stream in the main duct, a ser-ies of material redistribution units established along said main duct, each unit of which includes a separator for separating finely-divided material from gas, each of said units being connected into said main duct by a branch duct for withdrawing a yportion of the stream from the main duct, means for passing containing suspended dust from the separator of each of said units back into said main duct, a cyclone separator above the main supply bin and arranged to discharge material thereinto, and means including a return duct for recycling the stream of gas passing through the main duct down-stream of said units into the cyclone separator and then back to the main duct up-stream of the point of introduction of finely-divided material thereinto.

2. An apparatus for distributingr finely-divided' materials in a gas stream, comprising a series of material redistribution units, a separatorY for each unit, a main duct for carrying said gas stream containing said finely-divided material and extending along adjacent said units, means including a duct having a valve therein for withdrawing a controlled portion of the gas stream and iinely-divided material from said duct at each unit into the separator therefor while permitting ilow to any succeeding units. the sepa- -rator at each unit being adapted to separate iinely divided material from the gas stream withdrawn at each unit, means for returning the withdrawn gas stream containing suspended dust from which finely-divided material has been separated at each unit back into the duct at a point down-stream of the point of its withdrawal, and means for recycling the gas stream from a point down-stream of the last unit to the main duct up-stream of said units, whereby any dust and its quantity may be readily controlled by 'lli contained in the recycled gas stream is retained of material therefrom and sassi in the apparatus and not discharged into the atmosphere.

3. An apparatus (or handling finely divided materials comprising a supply bin for finelydivided material, a cyclone separator mounted above the supply bin for delivering separated finely-divided material to said bin, a conduit means for delivering finely-divided material in a gas stream to said cyclone separator, a series of material redistribution units, a main duct extending from the supply bin along said series of redistribution units, means for supplying nely-` divided material from the supply bin to said main duct, means for creating a gas stream in the main duct for carrying said finely-divided material, each of said redistribution units including a separator ior separating nely divided material from gas, a duct for each of said units connecting into said main duct for withdrawing a portion of the stream from the main duct into the separator of the unit, means for passing gas after separation of material therefrom and containing suspended duct from the separator of each of said units back into the main duct at a point down-stream of the point ot its withdrawal therefrom, a second cyclone separator arranged for delivering separated finely-divided material to said supply bin, means including a return duct for passing the stream of gas from the main duct down-stream of said units into said second cyclone separator, means for mingling the gas discharged from both oi said cyclone separators and for conducting at least a portion of the resulting gas mixture into said main duct in advance of said redistribution units.

GERHARD NIEMITZ.

REFERENCES CITED The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 1,203,703 -Chevalier Nov. 7, 1916 1,231,327 Brauchler June 26, 1917 1,468,966 Herington Sept. 25, 1923 1,541,903 Crites June 16, 1925 1,941,429 Berger Dec. 26, 1933 FOREIGN PATENTS Number Country Date 497,466 Germany Sept. 29, 1927 

